1. Field
The disclosed concept relates generally to motor control systems, and more particularly, to motor control centers. The disclosed concept also relates to subunits for motor control centers.
2. Background Information
Motor control centers are used, for example, in some commercial and industrial applications to distribute electrical power to a variety of loads (e.g., without limitation, relatively high power electrical motors, pumps, and other loads).
FIG. 1, for example, shows a portion of a motor control center 10. The motor control center 10 includes a multi-compartment enclosure 12 for receiving a plurality of motor control modules 14,16,18,20,22,24, commonly referred to as “buckets”. Typically, each bucket (see, e.g., bucket 22 of FIG. 1; also shown in FIG. 2) is a removable, pull-out subunit that has, or is installed behind, a door 26. The door 26 is preferably coupled to the housing 12 by hinges 28 (shown in phantom line drawing in FIG. 1) to permit access to motor control components of the bucket 22 while it is installed in the enclosure 12. For example and without limitation, the door 26 permits access to a circuit breaker assembly 30, a stab indicator 32, a shutter indicator 34, and a line contact actuator 36. When the bucket 22 is fully installed and electrically connected behind the door 26 of the enclosure 10, an operator may operate a disconnect handle 38. In a de-energized state of the motor control center 10, the operator may operate an isolation feature by moving a slide 40 and inserting crank 42 through a hole 43 in the door 26 to access the line contact actuator 36 to move a number of line contacts (see, for example, stab contacts 46,48,50 of the bucket 22 of FIG. 2) to an isolated position out of (see FIG. 2) electrical contact with power lines or buses 52 (partially shown in phantom line drawing in FIG. 2) of the motor control center 10. Motor control centers and subunits therefor are described in greater detail, for example, in commonly assigned U.S. Patent Application Publications 2009/0086414, 2008/0258667, 2008/0023211 and 2008/0022673, which are hereby incorporated herein by reference
There is room for improvement in motor control centers, and in subunits therefor.